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Global Warming in Nepal

INTRODUCTION 

There is a worldwide consensus that global warming is a real, rapidly advancing and widespread threat facing humanity this century. Scientists have presented evidence and tested models to substantiate this truly alarming fact (Permesan 1996, Pounds et al. 1999, IPCC 2001, Woodward 2002, Klanderud and Birks 2003, Hall and Fagre 2003). The evidence confirms that man‐made factors such as deforestation, agriculture, industries, automobiles, and the burning of fossil fuels, are contributing to Greenhouse Gas (GHG) emission, a major cause of global warming (IPCC 2001). The warming has manifold impacts on ecosystems and biological behaviours. Some widely discussed impacts include snow melting and glacier retreat, drought and desertification, flooding, frequent fire, sea level rise, species shifts, and heightened diseases incidence. These ecological and biological responses can consequently lead to serious consequences for human wellbeing (Easterling et al. 2000, Mehl and Karl 2000). Amid the plethora of literature available on the subject, the majority of people know very little about the causes and consequences of climate change, partially because the information is scattered and produced mostly in scientific language, obscured by jargon and sophisticated mathematical models. As a result, the information is beyond the reach of many concerned people. The information is even more scant for poor countries like Nepal, although such countries are vulnerable to climate change because of persistent poverty, illiteracy, and ignorance. The paucity of information impedes the task of effective policy formulation regarding adaptation and mitigation, making the poor countries more vulnerable. It is thus important to review current findings and develop a conceptual framework that is easily understandable to the general public, planners, policy makers and other non‐scientific audiences. It is equally important to explore how climate is changing, to examine how these changes are affecting ecosystems and human wellbeing, and finally to suggest ways to enhance local ability to adapt to the changing situation. We intend to: a) illustrate the effects of global warming on ecological factors such as temperature and precipitation, b) assess its impact on ecosystem processes and functions and ultimately c) examine its consequences for human wellbeing. We first present the scenarios from a global perspective and then analyze the destiny of Nepal based on available evidence, models, and predictions. This paper draws on a variety of literature from different regions throughout the world, with particular emphasis on high altitude and high latitude environments, and then makes inferences for Nepal. In addition, we collected some primary data on local perceptions and knowledge about climate change in the hilly regions of eastern Nepal. The findings were validated with and supplemented by additional ideas, wherever necessary, gathered through focus group discussions, key informant surveys, direct observations and consultations with experts.

GLOBAL WARMING AND GLOBAL CHANGE

Before talking about Nepal, it is important to discuss theoretical underpinnings of global warming and cite some examples from other parts of the world. Global warming is a globally distributed challenge and its consequences are widespread and alarming, with the nature and intensity of impacts varying over space and time. Global warming causes changes in climatic factors and affects ecosystems (ecological processes and functions) and biophysical systems. Many of these changes consequently yield negative consequences for human wellbeing. This whole process is depicted in figure 1 and elaborated below.


Temperature and precipitation are two important climatic factors affected by climate change in general and global warming in particular. Although global average temperature has warmed and cooled many times in the past, it has been constantly rising since the midtwentieth century and is likely to rise constantly in the future mainly due to an increased concentration of GHGs in the atmosphere. Without GHGs, the earth’s surface temperature would be 600 C cooler than it is today (Groom et al. 2007). Available data show that air temperature near the earth surface rose by 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during 20th century (IPCC 2007) and scientists estimate it could increase as much as 6.4 °C (11.5 °F) on average during the 21st century (Wigley 1999, IPCC 2007). The number of days with extreme heat in summer is increasing and winters are becoming warm and dry with less snow (Schiermeier 2008). Changes are also observed in the nature, intensity and frequency of precipitation. Scientists have observed odd patterns of rainfall throughout the world, but the results are mixed and distribution is uneven. More rain in terms of amount and intensity is experienced in higher altitude regions during the summer (Shrestha et al. 2000) and in the middle and high latitude regions of the Northern hemisphere, where frequencies of heavy precipitation events have already increased (Easterling et al. 2000). Changes in rainfall and temperature increasingly affect ecosystem processes and functions such as snow and ice melting, soil properties, and hydrological systems (IPCC 2001). Nearly half of the volume of the glaciers, or 30‐ 40% of the surface of the Swiss Alps was lost over the past 150 years. Likewise, Mt. Kenya and Mt. Kilimanjaro have lost 70% of their snow cover in the last century and projection confirms it will be completely lost by 2020 (Hastenrath and Greischnar 1997). It is also confirmed that over two thirds of the 150 glaciers that existed in Glacier National Park in the United States in 1850 disappeared by 1980 (Hall and Fagre 2003). While snow melting results in drought upstream, erosion and landslides arising from floods destroy farms, forests and other sources of livelihoods downstream (IPCC 2001, Easterling et al. 2000). In coastal areas, sea level rise caused by warming‐induced melting of ice and snow is even more threatening (Wigley 2005). Since 1990 the sea level has increased several folds and it is unlikely to stop for several decades to come (Barnett 1984, Nicholls and Hoozemans 1996, IPCC 2001, Douglas 2001, Pirages and Cousins 2005). Projections indicate that sea level rise will reach 280‐340 mm on average between 1990‐2100 (Church et al. 2006), and nearly 30% of this change will be attributable to ice melting (IPCC 2001). Warming also causes more extreme weather events such as hurricanes, storms, tornadoes, sea waves, tsunamis, etc. (Huang 2006). Drought and desertification, increased evapotranspiration, enhanced microbial activities, and altered physical and chemical properties of soil are other impacts most likely to result from global warming. Altered temperature, precipitation and ecosystem processes also affect the biological fabric in a variety of ways (Pounds et al. 1999). Range shift, phenology change, extinction, morphology and behaviour change are some of the biological changes linked to warming‐led ecosystem change (Table 1). Certain plant species shift to higher altitudes with the increased temperature (Woodward 2002, Klanderud and Birks 2003), causing insects and herbivores to shift with them (Whittaker 1999) and forcing carnivores to co‐migrate with their prey populations. During glacial period, when the earth was cooler than it is today, a large number of species were confined to the equator, but they slowly moved to higher latitudes as the weather became warmer. Scientists have confirmed latitudinal and altitudinal shifts of species at a rate of between 7 and 100 km per decade (Thomas and Lennon 1999, Parmesan 1996, Parmesan et al. 1999). Studies have also found trees growing at altitudes 40 meters higher than 25 years ago (NGS 2002). The shift in distribution is also obvious in marine fish (Perry et al. 2005, Brander 2007). Global warming has remarkable effects on the phenology of plants and the breeding behaviour of animals that are highly sensitive to photoperiod and heat. Several studies have already confirmed the change in breeding habits (e.g. courtship calling, birthing, mating, bird singing) in animals and insects, and in the blooming and flowering time of plants, from a few days to as early as a month before historical precedents (Hersteinsson and MacDonald 1992, Grabherr et al. 1994, Parmesan 1996, Pounds et al. 1999, Crozier 2003, available in Groom et al. 2007). These studies are also illustrated in figure 2. Several species may also become extinct due to gradual habitat loss caused by global warming, predominantly in tropical mountain biota above tree line, among rare alpine species (Sætersdal and Birks 1997, Holten 1998, Molau 2004, Ko¨rner 2004) and in high latitude and high altitude biomes (McCarthy 2001, Chapin et al. 2004, Rull and Vegas‐vilarru 2006). In Australia’s Snowy Mountains, warmer winters with less snowfall are threatening 250 species of plants (NGS 2002). The loss of the Golden Toad (Bufo periglenes) in Central America and the Bay checkerspot butterfly (Euphydryas editha bayensis) is also linked to global warming (Pounds and crump 1994, McLaughlin et al. 2002). IPCC’s 4th Assessment Report confirms that 20‐ 30% of species became extinct between the years 1980‐ 1999 and temperatures increased on average by 1.5‐2.5%. Thomas et al. (2004) suggest that 15‐37% of known plants and animals will be extinct or “committed to extinction” by 2050. Global warming is not only affecting climate and ecosystem, but it is also impacting human wellbeing. Warming affects various man‐dominated ecosystems and biophysical systems that support human wellbeing. Agriculture is affected most when drought adversely impacts rain‐fed agriculture, largely in developing countries where the majority of farmers practice subsistence agriculture. The African continent will have to bear a huge loss in yield from rain‐fed agriculture over the next decade or so. On the other hand, many other regions will face more intense and frequent flooding accompanied by landslides and erosion. As a result, soil carrying silt and debris can spoil valuable croplands (Preiser 2005, Pimental and Pimental 2006). Outbreaks of pests and disease will also become more prevalent in agricultural crops. Livestock will not escape from this trouble. Drought has already destroyed livestock in past. History shows, millions of people and several millions of livestock in Pakistan were killed when a drought prolonged for 3 years in South Asia during 1999‐2001.

Source : Journal of Forest and Livelihood 8(1) February 2009 Chaudhary and Aryal
Pashupati Chaudhary* and Kamal P. Aryal**
* University of Massachusetts, USA
** International Centre for Integrated Mountain Development (ICIMOD), Nepal
Corresponding author: pashupati.chaudhary@umb.edu

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